When conducting a non-destructive test using the optical properties of an analyzed subject, known processes generally use light having a wavelength in a near-infrared region or the like. A known process for measuring calories of food particularly uses the near-infrared light (e.g., patent document 1).
Such a process for measuring calories obtains the known calories, which are acquired by chemically analyzing samples of various food examples, and the near-infrared wavelength of calories of the various food samples acquired from a multiple regression analysis of the absorbance of each sample. The calories of a food that is the measured subject are estimated using the near-infrared wavelength.